Presario R3000 (Intel P4) Bios/Cmos question??

I'm having a problem with my Compaq Presario R3000 (Intel P4 model) notebook pc's BIOS settings. Seems like it loses the bios settings after maybe a week of computer use and then wants to load the setup defaults in order for WINXP Pro to boot properly. WINXP System clock settings revert to the year 1601 every time defaults are loaded. If I remove the laptop battery for any reason and then put it back in, it loses all bios settings I selected as well. It has the latest bios version (F.45) available. I thought maybe the CMOS battery needs to be replaced but I can find no reference to the R3000 having a replaceable CMOS battery in any of the COMPAQ support documents or parts listings. Opened up the laptop and couldn't find anything resembling a typical CMOS battery. I've googled for any references as well for a CMOS battery and have come up empty. Does anybody know if this is normal for the R3000 laptop to lose it's CMOS settings when you remove the laptop battery? Does it have a replaceable CMOS battery or is there a capacitor soldered to the board that's supposed to retain the settings? Any suggestions on what's causing the problem?